package leetcode;

public class RomanToInt {
    public static int romanToInt(String s){
        int sum = 0;
        int preNum = getValue(s.charAt(0));
        for (int i = 1;i < s.length();i++){
            int num = getValue(s.charAt(i));
            if(preNum < num){
                sum -= preNum;
            }else{
                sum += preNum;
            }
            preNum = num;
        }
        sum += preNum;
        return sum;
    }

    public static int getValue(char ch){
        switch (ch){
            case 'I': return 1;
            case 'V': return 5;
            case 'X': return 10;
            case 'L': return 50;
            case 'C': return 100;
            case 'D': return 500;
            case 'M': return 1000;
            default: return 0;
        }
    }

    public static void main(String[] args) {
        System.out.println(romanToInt("XXVII"));
    }
}
